This article describes a study conducted to identify mathematical practices in the activities developed by masons in the construction of brick houses. This research was developed with the builders of the city of Urucara. We used a qualitative approach through non-structured interviews with open questions and direct observation to uncover the ideas and mathematical reasoning present in the process, thereby showing the various situations linked to the construction of the home, these involving a practical knowledge that can be approached by observing the problem in relation to its theorization. The math concepts perceived during the construction process are: the metric relationships of the right triangle and regular quadrilateral, the calculation and measurement of the area, volume, and capacity, and the percentages of the rule of three. This study shows that it is possible to investigate the mathematic knowledge involved in distinct practices in order to contextualize and promote significant concepts and reveal a more enriching mathematics worthy of study.